Methods and apparatuses for proximity detection

ABSTRACT

The present disclosure relates to a concept of proximity detection. A sequence of keystrokes is captured when a person types on a keyboard placed on a support structure. A sequence of vibrations of the support structure in response to typing on the keyboard is captured with a sensor device associated with a user or a location and in contact with the support structure in proximity to the keyboard. The proximity between the person and the sensor device is checked based on a comparison of the captured sequence of keystrokes with the captured sequence of vibrations.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is based on PCT filing PCT/EP2019/054159, filedFeb. 20, 2019, which claims priority to EP 18164064.0, filed Mar. 26,2018, the entire contents of each are incorporated herein by reference.

FIELD

The present disclosure relates to methods and apparatuses for detectionof proximity between a person and a sensor device. Such methods andapparatuses can be used, among other things, for user authentication.

BACKGROUND

Signal integrity and/or user authentication is relevant to multiplefields. In computer science, for example, verifying a person's identityis often required to allow physical and/or logical access toconfidential data or systems, such as micropayment systems. The ways inwhich someone may be authenticated fall into three categories, based onsomething the person knows (e.g., a password, personal identificationnumber (PIN), challenge response (the person must answer a question, orpattern, etc.), something the person has (e.g., wrist band, ID card,security token, cell phone with built-in hardware or software token,etc.), and something the person is (e.g., fingerprint, retinal pattern,DNA sequence, signature, face, voice, unique bio-electric signals, orother biometric identifier). Authentication concepts can also combinetwo or more of the mentioned categories, wherein combinations usuallylead to more security.

It is desired to provide signal integrity and/or user authenticationconcepts that provide an increased level of protection from misuse ormalicious intrusion.

SUMMARY

This need is met by methods and apparatuses in accordance with theindependent claims. Advantageous embodiments are addressed by thedependent claims.

According to a first aspect, the present disclosure provides a method ofproximity detection. The methods includes capturing a sequence ofkeystrokes when a person types on a keyboard which is placed on asupport structure or substrate. The method further includes capturing,with a sensor device which is associated with a user and/or a locationand which is in contact with the support structure in proximity to thekeyboard, a sequence of vibrations of the support structure in responseto the person typing on the keyboard. The proximity between the persontyping and the sensor device is checked (confirmed or not confirmed)based on a comparison of the captured sequence of keystrokes with thecaptured sequence of vibrations.

According to a further aspect, it is provided a system for proximitydetection. The system comprises an input device with a keyboard placedon a support structure. The input device is configured to capture asequence of keystrokes when a person types on the keyboard. A sensordevice is in contact with the support structure in proximity to thekeyboard. The sensor device is associated with a user or a location andis configured to capture a sequence of vibrations of the supportstructure in response to the person typing on the keyboard. Controlcircuitry is configured to check the proximity between the person andthe sensor device based on a comparison of the captured sequence ofkeystrokes with the captured sequence of vibrations.

BRIEF DESCRIPTION OF THE FIGURES

Some examples of apparatuses and/or methods will be described in thefollowing by way of example only, and with reference to the accompanyingfigures, in which

FIG. 1 shows a schematic flow chart of a proximity detection methodaccording to an embodiment;

FIG. 2 shows a system for proximity detection according to anembodiment;

FIG. 3A, B show keystroke and vibration signals; and

FIG. 4 summarizes an example concept of proximity detection; and

FIG. 5 shows an example authentication process.

DETAILED DESCRIPTION

Various examples will now be described more fully with reference to theaccompanying drawings in which some examples are illustrated.

Accordingly, while further examples are capable of various modificationsand alternative forms, some particular examples thereof are shown in thefigures and will subsequently be described in detail. However, thisdetailed description does not limit further examples to the particularforms described. Further examples may cover all modifications,equivalents, and alternatives falling within the scope of thedisclosure.

The example embodiments described in the present disclosure can be usedas an additional factor for authentication which is based on theproximity between two different devices. It can be used on its own ortogether with other authentication factors (e.g., knowledge factors,possession factors, other biometrics) to achieve a frictionless way toauthenticate people.

FIG. 1 shows a schematic flowchart of a basic method 10 of proximitydetection.

Method 10 includes an act 11 of capturing a sequence of keystrokes whena person types on a keyboard which is placed on a support structure. Themethod 10 further includes an act 12 of capturing a sequence ofvibrations of the support structure due to the person typing on thekeyboard. Thereby the sequence of vibrations is captured or detected viaa sensor device which is associated with a certain user (which could bethe person typing or another user) and/or a specific location. The user-or location-specific sensor device is in contact with the supportstructure in proximity to the keyboard such that it can detectvibrations of the support structure. Method 10 further includes an act13 of checking or verifying the proximity between the person and thesensor device based on a comparison of the captured sequence ofkeystrokes with the captured sequence of vibrations.

When the person types on the keyboard this will inevitably causemechanical vibrations which are conveyed from the keyboard to thesupport structure and are conveyed further from the support structure tothe nearby sensor device. The vibrations reflect the rhythm ofkeystrokes during typing. The intensity of vibrations reaching thesensor device will—among others—also depend on the characteristics (e.g.material) of the support structure.

The support structure carrying the keyboard should be constructed tosufficiently convey such vibrations to the sensor device. An example ofthe support structure would be a table or, to be more specific, a tabletop on which the keyboard or another device including the keyboard (e.g.a PC, laptop computer, a tablet PC or any other device with a soft orhard keyboard) is placed. Other examples of the support structure wouldbe beds or couches.

The sensor device should be sensitive enough to detect the conveyedvibrations. For example, sensors available in nowadays mobile phones aretypically sensitive enough for this purpose. The sensor device caninclude a vibration sensor, such as an accelerometer, for example. Thesensor device can be included in a personal or trusted device associatedwith a user. Here, “associated with a user” can be understood asbelonging to the person, meaning that the person can be identified asbeing the user associated with the sensor device based on the sensordevice or another user- or location-specific device including avibration sensor. Examples of user-specific or personal devices aresmartphones, tablet PCs, or similar portable and personal communicationdevices, which can be assigned to a person via a Personal IdentificationNumber (PIN) of a subscriber identification module (SIM) or otherpersonal identifiers. Such portable personal communication devices canbe placed on the support structure (e.g., a table) in close proximity tothe keyboard in order to detect vibrations upon typing on the keyboard.

Another option would be that the vibration sensor device is associatedwith a specific location (e.g., a trusted location). For example, thesensor device could be installed in a specific building or a specificroom. More specifically, the sensor device could be loosely or fixedlyinstalled in or at the support structure such that it can detectvibrations originating from the keyboard via the support structure.

In some examples, act 13 includes confirming the proximity between theperson typing and the sensor device if a captured sequence of vibrationpeaks temporally corresponds to a captured sequence of keystroke pulses.Typically, every keystroke on the keyboard causes an electrical signalor an electrical signal pulse. The temporal sequence of these signalpulses can be monitored or captured. For example, this can be done by acomputer which is coupled with the keyboard. At the same time thevibrations caused by the sequence of keystrokes can be monitored by thepersonal sensor device, e.g. a smartphone. This will result in avibration sensor signal having minima and maxima. The courses of thekeyboard signal and the vibration sensor signal can be compared. Iftheir correlation is above a predefined threshold it can be decided thatthey match and thus that the device are close to each other. If it isbelow that threshold it can be decided that they do not match.

In some examples, act 13 can be performed by a processor that comprisesan input configured to receive information indicative of the sequence ofkeystrokes captured while typing on the keyboard, and an inputconfigured to receive, from the sensor device, information indicative ofa sequence of captured vibrations of the support structure in responseto typing on the keyboard. Thus, this processor can be coupled to thekeyboard and/or the sensor device via a wired or a wirelesscommunication interface. In some examples, the processor can becomprised of a computer including the keyboard, the sensor device, or aremote authentication server which can be connected with a computer andthe attached keyboard as well as with the sensor device via a network,such as the Internet, for example. Thus, information indicative of thecaptured sequence of keystrokes and/or the captured sequence ofvibrations can be sent to either a computer, the sensor device, or aremote comparison server, e.g. for authentication purposes.

Thus, in some embodiments, a computer can take input from a typing userthrough a keyboard and can derive from that a time sequence of typingevents. The computer can be a PC or a tablet or any other device with asoft or hard keyboard. The sensor device can be a personal device thatcaptures vibrations from this typing (passed on through the commonsupport structure between keyboard and sensor device). An entity canmatch the sequence of vibrations with the typing events sequence. Indifferent embodiments, depending on an employed authentication scenario,this entity can either be the computer, a remote service or the personaldevice. To do this matching the entity receives the typing eventssequence and the sequence of vibrations.

In some embodiments, the person can get authenticated if the proximitybetween the person and the sensor device is confirmed. The proximity ofthe personal device to the person typing on the keyboard makes it likelythat the person typing is the person owning the personal device. Invarious authentication scenarios the identity being confirmed is that ofthe owner of/user associated with the personal device. In somescenarios, the personal device can bring in more evidence that the ownerof the device is near, for example through evaluating “behaviometrics”on the personal device. Behaviometrics can offer a new generation ofinformation security solutions simply by using an individual itself asits core asset. This technique can be exploited by analyzing andmeasuring characteristics of the human behavior for verificationpurposes. For example, by analyzing how the person works with thekeyboard (typing rhythm) it is possible to recognize and confirm theidentity of a person.

There are several authentication scenarios to which embodiments of thepresent disclosure can be applied:

-   -   A computer (e.g. comprising the keyboard) gives access to the        person typing.    -   A computer accesses over a network a remote service (session        possibly initiated by the person typing). The authentication        gives the remote service authentication evidence of the person        typing.    -   A computer accesses over a local network (such as a Wireless        Local Area Network, WLAN) another device in the neighbourhood.

In some examples, an authentication status of the person can betransferred from or to the sensor device if the proximity between theperson and the sensor device has been confirmed. Such examples relate toso-called “hopping authentication”. For example, a person isauthenticating into a system while his/her personal communication device(e.g. smartphone) including the vibration sensor is on the table. In allthree above cases an authentication on the computer can be strengthenedwith hopping of authentication from the personal device to the computerin that the personal device can build up an internal authenticationscore/probability by gathering evidence that the person is near, forexample with behaviometrics. The transfer of the authentication scorefrom personal device to computer could be done by some securecommunication between the two. Alternatively, the authentication scoreof the personal device can be gathered in an authentication service inthe cloud, which would be facilitating authentication scenarios betweendevices.

In another example, authentication on the personal device can bestrengthened with hopping of authentication from the computer to thepersonal device in that the computer builds up an internalauthentication score by gathering evidence that the personal device isnear. Again various possible cases:

-   -   The person typing on the computer (including the keyboard) also        accesses the personal device. The authentication can control        this access.    -   The personal device accesses a remote service. The remote        service authenticates the person typing on the computer.    -   The personal device accesses over a local network another device        in the neighbourhood. The other device authenticates the person        typing on the computer.

For each of the example authentication scenarios the authentication caneither be a onetime authentication, a continuous authentication (if thedescribed proximity mechanism is regularly executed), or a continuationof a previous (recent) authentication (e.g. the person typing keepsaccess to the computer as long as her personal device stays near).

In various authentication schemes, the proximity can have differentroles:

-   -   The proximity is the only evidence for authentication (low        security)    -   The proximity is one of multiple factors contributing to the        authentication (as in a “multifactor authentication”).

For various authentication scenarios to be secure, trust relationshipscan be established. For example, the personal device can be registeredas a user's personal device in some way.

In some examples where the proximity is one of multiple factorscontributing to the authentication, the sequence of keystrokes can becaptured while the person is typing authentication information via thekeyboard. The person can then be authenticated if

-   -   the captured sequence of keystrokes corresponds to predefined        authentication information, and    -   a captured sequence of vibration peaks temporally corresponds to        a captured sequence of keystroke pulses.

In such examples, the possession of the user-specific sensor device(e.g. smartphone) close to the keyboard can be regarded as a secondfactor authentication. It is thus proposed that the user-specific sensordevice or smartphone is close to a place where the person isauthenticating. It is assumed that the smartphone including thevibration sensor is not stolen or handed over to somebody else. In otherwords, it is assumed that the identity of the user associated with thesensor device corresponds to the identity of the person that needs to beconfirmed. Also another authentication mechanism could be in use thatconfirms whether or not the smartphone is on the body of the user withwhom the sensor device is associated. In the latter case the smartphonecould measure a body parameter, such as heart rate or temperature, as athird factor for authentication, for example.

In some examples, the person can be kept authenticated (after successfulinitial authentication) as long as a captured sequence of vibrationpeaks temporally matches a sequence of keystroke pulses captured duringa communication session. Such a continuous monitoring and comparison ofkeystrokes and resulting vibrations during the communication session canfurther increase the security level.

FIG. 2 illustrates an example scenario how embodiments of the presentdisclosure can be applied.

A person 21 places his associated personal communication device 22 on atable 23 next to a keyboard 24 which is coupled to a computer 25 via awireless or wired link. The person 21 types on the keyboard 24, forexample for accessing an web-service or the like. This webservice can beaccessed via predefined authentication information such as a user nameand/or a personal password. The person's typing is detected by thepersonal communication device 22 and by the keyboard 24 at the sametime.

The skilled person having benefit from the present disclosure willappreciate that due to privacy issues it is not mandatory to capture theactual keys (e.g. “q”, “w”, “e”, etc.) the person 21 presses. Instead,it may be sufficient to capture the time a key is pressed and/orreleased, leading to a time sequence of keystrokes. An example of a timesequence 31 of keystrokes (or a corresponding electrical signal) issketched in FIG. 3A. For example, a remote server 26 or the computer 25could ask permission to the person for logging the keys pressed.Capturing the time sequence 31 of keystrokes can be done via a webapplication capturing the keys pressed during login or by means of anyanother type of key-logger. The captured/monitored time sequence ofkeystrokes or information indicative thereof can then be send to a(remote) comparison server 26.

At the same time the user's personal communication device 22 placed onthe table or desk 23 can detect the vibrations of the table 23 due tothe keystrokes via a built-in acceleration sensor. The capturedacceleration data can then also be send to comparison server 26, e.g.via a wireless interface in accordance with a present or future wirelesscommunications standard. FIG. 3B sketches an example of a capturedacceleration signal 32. In an example embodiment, the person 21 could beasked to place the personal communication device 22 on the table 23while typing on the keyboard 24. If the personal communication device 22is not on the table no vibrations can be detected and thus theauthentication will fail. The personal communication device 22 could beconfigured to permanently log acceleration data while being placed onthe table 23.

In an alternative embodiment the acceleration or vibration sensor couldalso be built into the table 23 and be uniquely associated with thetable 23. This would be an example of a location-specific sensor device.Such embodiments can also provide an additional level of security overconventional art.

Both signals 31, 32 corresponding to the time sequence of keystrokes andthe captured acceleration can be compared at comparison server 26. Note,however, that the signals 31, 32 can be of different nature. While wecould have timestamps from the keyboard 24, we could have accelerationsamples from the personal communication device 22. Thus, the comparisonserver 26 could be configured to determine peaks from the accelerationdata, to extract timestamps of the peaks, and to compare the latter tothe timestamps of the keyboard 24. In another example, the comparisonserver 26 could be configured to covert each captured keystroke pulse toa Gaussian pulse and to correlate the resulting sequence of Gaussianpulses with the captured acceleration data.

The comparison process is summarized in FIG. 4. The acceleration signal32 measured by the personal communication device 22 or its accelerationsensor is compared with the sequence 31 of keystrokes from the keyboard24. Based on the comparison of both signals its is decided whether theuser's personal communication device 22 and the keyboard 24 are close.If yes, the person can be authenticated, or authentication can betransferred between the devices, for example.

Typically, authentication succeeds if several authentication factorsconfirm that the identity of the person 21 corresponds to the user thatneeds to be authenticated. None of these factors brings perfectknowledge, but instead they can all increase the likelihood that theperson 21 is present. This is typically expressed with a confidencescore. The overall confidence score can be derived from confidencescores associated with the different authentication factors, either in aheuristic way or based on statistical reasoning. Here, it is proposedthat one of the factors used for an authentication on computer 25 can bethe proximity between the computer 25/keyboard 24 and the personalcommunication device 22 of the person 21. The confidence score of thecomputer authentication can be increased when such a proximity isconfirmed. In some examples it is also possible that the personalcommunication device 22 also runs an authentication mechanism thatconfirms that the personal communication device 22 is near the person21. In this case the authentication score on the computer authenticationcan depend on the confidence score reached on the smartphone.

An example multi-factor authentication process 50 is schematically shownin FIG. 5.

A first authentication factor or level is determined by predefinedauthentication information including a login (user name) and/or apassword. It is checked whether the captured sequence of keystrokescorresponds to this predefined authentication information, see act 51.If yes, the authentication process 50 can continue to the secondfactor/level, the proximity check 52. If no, the authentication fails,see reference numeral 53. During the proximity check 52 it is checkedwhether a captured sequence of vibration peaks (coming from thesmartphone) temporally corresponds to a captured sequence of keystrokepulses (from the keyboard). If yes, it can be concluded that bothdevices are close and authentication is correct. Otherwiseauthentication fails.

To summarize, the proposed idea comprises in detecting the typing on thecomputer keyboard on two different devices,

-   -   on a keyboard, capturing the times when the keys are pressed and        released,    -   on personal communication device (e.g., smartphone), using an        accelerometer to capture the vibrations of the support structure        due to key pressing.

Both signals can be sent to a server to compare them (or from one deviceto the other). The comparison of both signals can be calculated. If theyare similar, then the personal communication device was close to theplace where the person was typing. If they are not, the personalcommunication device and the keyboard are not close.

In other words, some examples propose a concept for performingmulti-factor authentication using a personal communication device placedin proximity to a keyboard. The concept comprises capturing timestampswhen the keys on the keyboard are pressed and released, capturingvibrations of a table due to key pressing, using an accelerometer of thepersonal communication device. The signals obtained from the keyboardand the smartphone are compared (on a server or either device) toauthenticate the person. For example, the comparison can be performedbetween the acceleration peaks and the timestamps of the peaks. Foranother example, the timestamps can be converted in time series with thetimestamps as Gaussian and the resultant can be correlated with theacceleration data.

The following examples pertain to further embodiments.

-   (1) A method of proximity detection The method comprises capturing a    sequence of keystrokes when a person types on a keyboard placed on a    support structure, capturing, with a sensor device associated with a    user or a location and being in contact with the support structure    in proximity to the keyboard, a sequence of vibrations of the    support structure in response to typing on the keyboard, and    checking the proximity between the person and the sensor device    based on a comparison of the captured sequence of keystrokes with    the captured sequence of vibrations.-   (2) The method of (1), wherein checking the proximity comprises    confirming the proximity between the person and the sensor device if    a captured sequence of vibration peaks temporally corresponds to a    captured sequence of keystroke pulses.-   (3) The method of any one of (1) to (2), further comprising    authenticating the person as the user associated with the sensor    device if the proximity between the person and the sensor device is    confirmed.-   (4) The method of any one of (1) to (3), wherein the sequence of    keystrokes is captured when typing authentication information via    the keyboard, and wherein the method further comprises    authenticating the person as the user associated with the sensor    device if the captured sequence of keystrokes corresponds to    predefined authentication information and if a captured sequence of    vibration peaks temporally corresponds to a captured sequence of    keystroke pulses.-   (5) The method of (4), further comprising keeping the person    authenticated as long as a captured sequence of vibration peaks    temporally matches a sequence of keystroke pulses captured during a    communication session.-   (6) The method of any one of (1) to (5), further comprising    transferring an authentication status of the person to the sensor    device if the proximity between the person and the sensor device is    confirmed.-   (7) The method of any one of (1) to (6), further comprising sending    information indicative of the captured sequence of keystrokes and    the captured sequence of vibrations to a remote server.-   (8) The method of any one of (1) to (7), wherein the sequence of    keystrokes is captured with an accelerometer of the sensor device.-   (9) The method of any one of (1) to (8), wherein the sensor device    is integrated in the support structure.-   (10) The method of any one of (1) to (8), wherein the sequence of    keystrokes is captured with a mobile communication device associated    with a user.-   (11) The method of (10), wherein the mobile communication device is    a smartphone or tablet PC belonging to a user.-   (12) The method of any one of (1) to (11), wherein the support    structure for the keyboard is a table top.-   (13) The method of any one of (1) to (12), wherein checking the    proximity between the person and the sensor device is one of at    least two factors contributing to an authentication of the person.-   (14) A proximity detection device, comprising an input configured to    receive information indicative of a sequence of keystrokes captured    while typing on a keyboard placed on a support structure, an input    configured to receive, from a sensor device associated with a user    or a location and being in contact with the support structure in    proximity to the keyboard, information indicative of a sequence of    captured vibrations of the support structure in response to typing    on the keyboard, and a processor configured to check the proximity    between the person and the sensor device based on a comparison of    the captured sequence of keystrokes with the captured sequence of    vibrations.-   (15) The proximity detection device of (14), wherein the proximity    detection device comprises an authentication server.-   (16) The proximity detection device of (15), wherein the    authentication server is configured to authenticate the person if a    captured sequence of keystrokes pulses matches a captured sequence    of vibrations peaks.-   (17) A system for proximity detection, the system comprising an    input device comprising a keyboard placed on a support structure,    wherein the input device is configured to capture a sequence of    keystrokes when typing on the keyboard, a sensor device being in    contact with the support structure in proximity to the keyboard,    wherein the sensor device is associated with a user or a location    and configured to capture a sequence of vibrations of the support    structure in response to the typing on the keyboard, and control    circuitry configured to check the proximity between the person and    the sensor device based on a comparison of the captured sequence of    keystrokes with the captured sequence of vibrations.-   (18) The system of (17), wherein the control circuitry is comprised    of a remote server, wherein the sensor device is configured to send    information indicative of the captured sequence of vibrations to the    remote server, and wherein the input device is configured to send    information indicative of the captured sequence of keystrokes to the    remote server.-   (19) The system of (17) or (18), wherein the sensor device is a    smartphone or tablet PC belonging to the person and comprising an    accelerometer to measure vibrations.

The aspects and features mentioned and described together with one ormore of the previously detailed examples and figures, may as well becombined with one or more of the other examples in order to replace alike feature of the other example or in order to additionally introducethe feature to the other example.

Examples may further be or relate to a computer program having a programcode for performing one or more of the above methods, when the computerprogram is executed on a computer or processor. Steps, operations orprocesses of various above-described methods may be performed byprogrammed computers or processors. Examples may also cover programstorage devices such as digital data storage media, which are machine,processor or computer readable and encode machine-executable,processor-executable or computer-executable programs of instructions.The instructions perform or cause performing some or all of the acts ofthe above-described methods. The program storage devices may comprise orbe, for instance, digital memories, magnetic storage media such asmagnetic disks and magnetic tapes, hard drives, or optically readabledigital data storage media. Further examples may also cover computers,processors or control units programmed to perform the acts of theabove-described methods or (field) programmable logic arrays ((F)PLAs)or (field) programmable gate arrays ((F)PGAs), programmed to perform theacts of the above-described methods.

The description and drawings merely illustrate the principles of thedisclosure. Furthermore, all examples recited herein are principallyintended expressly to be only for pedagogical purposes to aid the readerin understanding the principles of the disclosure and the conceptscontributed by the inventor(s) to furthering the art. All statementsherein reciting principles, aspects, and examples of the disclosure, aswell as specific examples thereof, are intended to encompass equivalentsthereof.

A functional block denoted as “means for . . . ” performing a certainfunction may refer to a circuit that is configured to perform a certainfunction. Hence, a “means for s.th.” may be implemented as a “meansconfigured to or suited for s.th.”, such as a device or a circuitconfigured to or suited for the respective task.

Functions of various elements shown in the figures, including anyfunctional blocks labeled as “means”, “means for providing a signal”,“means for generating a signal.”, etc., may be implemented in the formof dedicated hardware, such as “a signal provider”, “a signal processingunit”, “a processor”, “a controller”, etc. as well as hardware capableof executing software in association with appropriate software. Whenprovided by a processor, the functions may be provided by a singlededicated processor, by a single shared processor, or by a plurality ofindividual processors, some of which or all of which may be shared.However, the term “processor” or “controller” is by far not limited tohardware exclusively capable of executing software, but may includedigital signal processor (DSP) hardware, network processor, applicationspecific integrated circuit (ASIC), field programmable gate array(FPGA), read only memory (ROM) for storing software, random accessmemory (RAM), and non-volatile storage. Other hardware, conventionaland/or custom, may also be included.

A block diagram may, for instance, illustrate a high-level circuitdiagram implementing the principles of the disclosure. Similarly, a flowchart, a flow diagram, a state transition diagram, a pseudo code, andthe like may represent various processes, operations or steps, whichmay, for instance, be substantially represented in computer readablemedium and so executed by a computer or processor, whether or not suchcomputer or processor is explicitly shown. Methods disclosed in thespecification or in the claims may be implemented by a device havingmeans for performing each of the respective acts of these methods.

It is to be understood that the disclosure of multiple acts, processes,operations, steps or functions disclosed in the specification or claimsmay not be construed as to be within the specific order, unlessexplicitly or implicitly stated otherwise, for instance for technicalreasons. Therefore, the disclosure of multiple acts or functions willnot limit these to a particular order unless such acts or functions arenot interchangeable for technical reasons. Furthermore, in some examplesa single act, function, process, operation or step may include or may bebroken into multiple sub-acts, -functions, -processes, -operations or-steps, respectively. Such sub acts may be included and part of thedisclosure of this single act unless explicitly excluded.

Furthermore, the following claims are hereby incorporated into thedetailed description, where each claim may stand on its own as aseparate example. While each claim may stand on its own as a separateexample, it is to be noted that—although a dependent claim may refer inthe claims to a specific combination with one or more other claims—otherexamples may also include a combination of the dependent claim with thesubject matter of each other dependent or independent claim. Suchcombinations are explicitly proposed herein unless it is stated that aspecific combination is not intended. Furthermore, it is intended toinclude also features of a claim to any other independent claim even ifthis claim is not directly made dependent to the independent claim.

The invention claimed is:
 1. A method of proximity detection,comprising: capturing a sequence of keystrokes when a person types on akeyboard placed on a support structure; capturing, with a sensor deviceassociated with a user or a location and in contact with the supportstructure in proximity to the keyboard, a sequence of vibrations of thesupport structure in response to the typing of the sequence ofkeystrokes on the keyboard; checking proximity between the person andthe sensor device based on a comparison of the captured sequence ofkeystrokes with the captured sequence of vibrations, wherein saidchecking the proximity includes confirming the proximity between theperson and the sensor device when a captured sequence of vibration peakstemporally corresponds to a captured sequence of keystroke pulses;authenticating the person as the user associated with the sensor deviceunder a condition that the proximity between the person and the sensordevice is confirmed and based on behaviometrics in the form of typingrhythm of the captured sequence of keystrokes; and keeping the personauthenticated as long as one or more post-authentication capturedsequences of vibration peaks temporally matches a corresponding one ormore post-authentication sequences of keystroke pulses captured during acommunication session.
 2. The method of claim 1, wherein the sequence ofkeystrokes is captured when typing authentication information via thekeyboard, and wherein the method further comprises performing saidauthenticating the person as the user associated with the sensor devicewhen the captured sequence of keystrokes corresponds to predefinedauthentication information and when a captured sequence of vibrationpeaks temporally corresponds to a captured sequence of keystroke pulses.3. The method of claim 1, further comprising transferring anauthentication status of the person from or to the sensor device whenthe proximity between the person and the sensor device is confirmed. 4.The method of claim 1, further comprising sending information indicativeof the captured sequence of keystrokes and the captured sequence ofvibrations to a remote server.
 5. The method of claim 1, wherein thesequence of keystrokes is captured with an accelerometer of the sensordevice.
 6. The method of claim 1, wherein the sensor device isintegrated in the support structure.
 7. The method of claim 1, whereinthe support structure for the keyboard is a table top.
 8. The method ofclaim 1, wherein said checking the proximity between the person and thesensor device is one of at least two factors contributing to theauthentication of the person, checking the behaviometrics in the form ofthe typing rhythm of the captured sequence of keystrokes being anotherof the factors contributing to the authentication of the person.
 9. Aproximity detection device, comprising: an input configured to receiveinformation indicative of a sequence of keystrokes captured while typingon a keyboard placed on a support structure; an input configured toreceive, from a sensor device associated with a location and in contactwith the support structure in proximity to the keyboard, informationindicative of a sequence of captured vibrations of the support structurein response to the typing of the sequence of keystrokes on the keyboard;and a processor configured to check proximity between the person and thesensor device based on a comparison of the captured sequence ofkeystrokes with the captured sequence of vibrations, wherein thechecking the proximity includes confirming the proximity between theperson and the sensor device when a captured sequence of vibration peakstemporally corresponds to a captured sequence of keystroke pulses,authenticate the person as the user associated with the sensor deviceunder a condition that the captured sequence of keystrokes pulsesmatches the captured sequence of vibrations peaks, and keep the personauthenticated as long as one or more post-authentication capturedsequences of vibration peaks temporally matches a corresponding one ormore post-authentication sequences of keystroke pulses captured during acommunication session and based on behaviometrics in the form of typingrhythm of the captured sequence of keystrokes.
 10. The proximitydetection device of claim 9, wherein the proximity detection devicecomprises an authentication server.
 11. A system for proximitydetection, the system comprising: an input device comprising a keyboardplaced on a support structure, wherein the input device is configured tocapture a sequence of keystrokes when typing on the keyboard; a sensordevice in contact with the support structure in proximity to thekeyboard, wherein the sensor device is associated with a user andconfigured to capture a sequence of vibrations of the support structurein response to the typing of the sequence of keystrokes on the keyboard;and control circuitry configured to check proximity between the personand the sensor device based on a comparison of the captured sequence ofkeystrokes with the captured sequence of vibrations, wherein thechecking the proximity includes confirming the proximity between theperson and the sensor device when a captured sequence of vibration peakstemporally corresponds to a captured sequence of keystroke pulses,authenticate the person as the user associated with the sensor deviceunder a condition that the proximity between the person and the sensordevice is confirmed and based on behaviometrics in the form of typingrhythm of the captured sequence of keystrokes, and keep the personauthenticated as long as one or more post-authentication capturedsequences of vibration peaks temporally matches a corresponding one ormore post-authentication sequences of keystroke pulses captured during acommunication session and based behaviometrics in the form of typingrhythm of the captured sequence of keystrokes.
 12. The system of claim11, wherein the control circuitry is comprised of a remote server,wherein the sensor device is configured to send information indicativeof the captured sequence of vibrations to the remote server, and whereinthe input device is configured to send information indicative of thecaptured sequence of keystrokes to the remote server.
 13. The system ofclaim 11, wherein the sensor device is a smartphone or tablet PCbelonging to the person and comprising an accelerometer to measurevibrations.